"What makes you smile?" Certainly not an unsettling grin. As if the film's unnerving premise isn't spine-chilling enough, Paramount Pictures unveiled—or in this case, unzipped—a new poster for the upcoming horror flick, Smile, with a short yet frightening warning that says, "Once you see it, it's too late," teasing that the whole creepy grin thing is a contagion.

Director Parker Finn's horror debut, starring Sosie Bacon, tells the unbelievable experiences of the psychiatrist Dr. Rose Cotter, who has witnessed an incident that involves one of her patients. When the occurrence starts to take a toll on her sanity, she tries to uncover the reason behind the dreadful murders and the horrifying wide smiles that seem to be a plague, killing people who are infected. Finn's upcoming film is an adaptation of his 2020 short film Laura Hasn't Slept, which instantly became a critical darling, winning the SXSW Film Festival's special jury recognition Midnight Award. The film starred Caitlin Stasey, who is set to also play an undisclosed role in Smile. But while she's not taking over the lead role, Stasey is the woman who can be seen in the chilling new poster.

The film's official synopsis reads: "After witnessing a bizarre, traumatic incident involving a patient, Dr. Rose Cotter (Sosie Bacon) starts experiencing frightening occurrences that she can't explain. As an overwhelming terror begins taking over her life, Rose must confront her troubling past in order to survive and escape her horrifying new reality."

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Image via Paramount

Related: 'Smile': Release Date, Trailer, Cast, and Everything We Know So Far

The forthcoming film has been rated R for its violent content, so while October is still a month and a half away, you can expect to receive an early Halloween treat from the film's grisly story. Smile will also mark Bacon's first lead role in on the big screen.

Bacon can also be seen in the anthology series Scream: The TV Series based on Wes Craven's Scream franchise. Kyle Gallner (A Nightmare on Elm Street), Jessie T. Usher (Dangerous Lies), Robin Weigert (The Undying), Kal Penn (The Sisterhood of Night), and Rob Morgan (The Unforgivable) round out the cast of Smile.

Smile hits theaters on September 30. You can check the terrifying poster and trailer below:

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